bottle collection vs collecting

bottle collection and collecting both are nouns.

Word	Noun	Adjective	Verb	Adverb
bottle collection	Yes	No	No	No
collecting	Yes	No	No	No

As nouns, collecting is a hypernym of bottle collection; that is, collecting is a word with a broader meaning than bottle collection:

Other hypernyms of bottle collection include aggregation, assembling, collection.

bottle collection (noun)	collecting (noun)
the activity of collecting bottles	the act of gathering something together
collecting bottles for reuse
a collection of bottles